The present invention is related to monitors and, more particularly, to a auto sync circuit for use in a personal computer (PC) monitor to provide the latter compatibility with the variety of graphic output signals supplied from different manufacturers PC's.
Different PC's provide different graphic output signals for driving a monitor. For example, a PC may supply separate TTL horizontal and vertical sync pulses of either negative or positive polarities, a TTL composite sync output of either polarity or even analog RGB sync outputs. It is desirable that a monitor be able to receive these different graphic outputs so that it is compatible with any PC.
There is at least one prior art monitor that provides compatibility with the different graphic output signals discussed above. One disadvantage of this prior art monitor is that a mechanical switch and discrete components are required for switching the monitor between TTL sync and analog composite sync input signals.
It is desirable to provide true automatic multisync compatibility by eliminating the need for mechanical switching while reducing discrete component count.